A very ingenious call-bell or annunciator for use with inductive or conductive systems of wireless telegraphy was invented and described in 1898 by S.
Fahie, A History of Wireless Telegraphy (Edinburgh, 1899); J.
This method of communication by magnetic induction through space establishes, therefore, a second method of wireless telegraphy which is quite independent of and different from that due to conduction through earth or water.
Marconi's success in bridging the English Channel at Easter in 1899 with electric waves and establishing practical wireless telegraphy between ships and the shore by this means drew public attention to the value of the new means of communication.
Braun showed that oscillations suitable for the purposes of electric wave creation in wireless telegraphy could be set up in a circuit consisting of a Leyden jar or jars, a spark gap and an inductive circuit, and communicated to an antenna either by inductive or direct coupling (Brit.
Erskine-Murray, A Handbook of Wireless Telegraphy (1907); J.
In practical wireless telegraphy the antenna is generally a collection of wires in fan shape upheld from one or more masts or wooden towers.
Up to 1895 or 1896 the suggestions for wireless telegraphy which had been publicly announced or tried can thus be classified under three or four divisions, based respectively upon electrical conduction through the soil or sea, magnetic induction through space, combinations of the two foregoing, and lastly, electrostatic induction.
Many other more or less imperfect devices - such as those of Mahlon Loomis, put forward in 1872 and 1877, and Kitsee in 1895 - for wireless telegraphy were not within the region of practically realizable schemes.
Leyden jars are now much employed for the production of the high frequency electric currents used in wireless telegraphy (see Telegraphy, Wireless).